bug.h: add include of it to various implicit C users

With bug.h currently living right in linux/kernel.h there
are files that use BUG_ON and friends but are not including
the header explicitly.  Fix them up so we can remove the
presence in kernel.h file.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/gpu/drm/radeon/cayman_blit_shaders.c b/drivers/gpu/drm/radeon/cayman_blit_shaders.c
index 7b4eeb7..19a0114 100644
--- a/drivers/gpu/drm/radeon/cayman_blit_shaders.c
+++ b/drivers/gpu/drm/radeon/cayman_blit_shaders.c
@@ -24,6 +24,7 @@
  *     Alex Deucher <alexander.deucher@amd.com>
  */
 
+#include <linux/bug.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 
diff --git a/drivers/gpu/drm/radeon/evergreen_blit_shaders.c b/drivers/gpu/drm/radeon/evergreen_blit_shaders.c
index 3a10399..f85c0af 100644
--- a/drivers/gpu/drm/radeon/evergreen_blit_shaders.c
+++ b/drivers/gpu/drm/radeon/evergreen_blit_shaders.c
@@ -24,6 +24,7 @@
  *     Alex Deucher <alexander.deucher@amd.com>
  */
 
+#include <linux/bug.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 
diff --git a/drivers/gpu/drm/radeon/r600_blit_shaders.c b/drivers/gpu/drm/radeon/r600_blit_shaders.c
index 2d1f6c5..3af3c64 100644
--- a/drivers/gpu/drm/radeon/r600_blit_shaders.c
+++ b/drivers/gpu/drm/radeon/r600_blit_shaders.c
@@ -24,6 +24,7 @@
  *     Alex Deucher <alexander.deucher@amd.com>
  */
 
+#include <linux/bug.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 
diff --git a/drivers/staging/wlags49_h2/hcf.c b/drivers/staging/wlags49_h2/hcf.c
index b0087733..5957c3a 100644
--- a/drivers/staging/wlags49_h2/hcf.c
+++ b/drivers/staging/wlags49_h2/hcf.c
@@ -91,6 +91,7 @@
 #include "hcf.h"                // HCF and MSF common include file
 #include "hcfdef.h"             // HCF specific include file
 #include "mmd.h"                // MoreModularDriver common include file
+#include <linux/bug.h>
 #include <linux/kernel.h>
 
 #if ! defined offsetof